Solid electrolyte batteries are based on the principle of a solid electrolyte fuel cell, which is supplemented by additional ceramic storage bodies for use as a battery. Metal or metal oxide particles are incorporated in a ceramic matrix of these storage bodies. To draw energy from this battery, the metal particles are electrochemically converted to the corresponding oxides using oxygen, in which case the energy which is released can be drawn as electrical energy at the tapping poles of the battery. To recharge a battery of this type, the component parts of the battery which are equivalent to a solid oxide fuel cell are operated in electrolysis mode, so that the electrical energy which is supplied forms hydrogen, which can reduce the metal oxides back to the corresponding metals.
The accessibility of the incorporated metal or metal oxide particles and also the active surface area thereof are of particular importance for the capacity and also the charging and discharging characteristics of such a battery. At present, substantially spherical or ellipsoidal metal particles having a median grain size d50 of less than 10 μm are commonly used. However, particles of this type have a high reactivity and thus tend toward rapid mutual sintering at the high operating temperatures of a solid electrolyte battery. By virtue of this sintering, the majority of the active surface area of the particles is lost, and therefore the storage elements of a battery designed in such a way exhibit rapid aging.